JPH08121393A - Closed type pump - Google Patents

Abstract

PURPOSE: To improve the efficiency of a pump as cavitation is prevented from occurring. CONSTITUTION: Formation of a closed type pump is such that a plurality of vanes 17 are arranged between the front shroud 16 and the rear shroud 15 of an impeller 14 rotationally driven by a drive shaft 13. The inner edge 17a on the inlet side of fluid of an adjacent vane 17 on one side is formed in a shape of inclination toward approximately the central side of the front shroud 16 from the rear side and meanwhile, the the inner edge 17c on the fluid inlet side of the vane 17 on the other side is formed in a shape of inclination toward approximately the central side of the rear shroud 15 from the front side. The inner edges 17a and 17c are formed in a cross shape and the total area of a fluid inlet in the vicinity of the inner edges 17a and 17c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a water pump, particularly a closed type pump, used in a water cooling type cooling device for an internal combustion engine of an automobile, for example.

[0002]

2. Description of the Related Art Generally, as a water pump used in a water-cooled cooling apparatus for an internal combustion engine, an open type pump having a plurality of vanes provided on the outer periphery of a rotor and a plurality of vanes provided between front and rear shrouds are provided. There is a closed type pump, and as an example of this closed type pump, the one described in Japanese Utility Model Publication No. 58-177584 is known.

To explain the outline with reference to FIG. 5, a drive shaft 3 which is rotationally driven by a crank shaft of an engine is inserted and supported at one end of a pump chamber 2 formed inside a pump housing 1, and a pump is also provided. An impeller 4 is rotatably arranged inside the chamber 2. The impeller 4 has an inner peripheral portion 5
a is fixed to the front end portion of the drive shaft 3 via a nut 10, a front shroud 6 located in front of the rear shroud 5 and having a substantially arcuate cross section, and both shrouds 5, 6 And a plurality of vanes 7 radially provided between the two.

The rear shroud 5 has an inner peripheral portion 5a formed with a balancing hole 5b for reducing axial thrust.
A restricting portion 5c that restricts the flow of the fluid flowing out from the balancing hole 5b in the outer peripheral direction is integrally provided at the approximate center of the back surface. The plurality of vanes 7 are spirally bent in the direction opposite to the rotation direction, and each inner end edge 7a has a fluid inlet 8a.
On the other hand, the outer edge 7b extends to the fluid outlet 9 near the outer peripheral edges of both shrouds 5 and 6.

When the impeller 4 rotates with the rotation of the drive shaft 3, the cooling water flowing from the cooling water supply passage (not shown) into the fluid inlet 8 causes the facing surfaces of the vanes 7 and the front and rear shrouds 5 and 6. Flowing out from the fluid outlet 9 side along the facing inner surface of
It is forcibly supplied in the water jacket of the engine.

[0006]

However, in the above-mentioned conventional closed type pump, the inner end edges 7a of the vanes 7 are inclined from the front shroud 6 toward the inner peripheral portion 5a of the rear shroud 5 at the same inclination angle. Is formed in. Therefore, in order to improve the pump efficiency, the vanes 7 of the same shape
If the number of the above is simply increased, the overall wall thickness of each inner end edge 7a of the vane 7 increases, and the total area of the fluid inlet 8 near each inner end edge 7a decreases.

As a result, the pressure of the cooling water in the vicinity of the fluid inlet 8 is lowered to easily cause cavitation, and at the same time, the cooling water collides with each inner edge 7a to reduce the pump efficiency. There is a fear of being lost.

[0008]

The present invention has been devised in view of the above problems of the prior art, and a plurality of vanes are provided between a front shroud and a rear shroud of an impeller rotatably driven by a drive shaft. In the closed type pump for causing the fluid flowing into the fluid inlet provided on the inner peripheral side of the front and rear shrouds to flow out along the spiral inner surface of each vane with the rotation of the impeller, the adjacent one vane The inner edge of the fluid inlet side of the is formed in a downward slope from the rear shroud toward the approximate center side of the front shroud, and the inner edge of the other vane on the inlet side is formed from the front shroud to the rear side. It is characterized in that the shroud is formed in a downwardly sloping shape toward the approximate center side.

[0009]

Since each inner edge of the adjacent vanes is formed in an inclined shape so as to cross each other with respect to the inner peripheral portions of the front and rear shrouds, the total fluid inlet area near each inner edge is growing. That is, since the vanes whose inner edges are inclined in the same direction as the conventional ones are arranged at intervals of one sheet in the circumferential direction, the area of the fluid inlet becomes larger accordingly. Therefore, even if the number of vanes is increased, the reduction of the inlet area is prevented.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1 and 2 show an embodiment of a closed type pump of the present invention, 11 is a pump housing having a pump chamber 12 inside, 13 is a penetrating support at one end of the pump housing 11, and is a crank of an engine. A drive shaft is rotationally driven by the shaft, and 14 is a rotatable impeller fixed to the tip of the drive shaft 13 in the pump chamber 12.

The impeller 14 is integrally fixed between a rear shroud 15 having a substantially circular shape, a front shroud 16 arranged in front of the rear shroud 15, and facing surfaces of the shrouds 15, 16. And a plurality of vanes 17.

The rear shroud 15 is fixed to the drive shaft 13 through the central hole of the relatively thick inner peripheral portion 15a, and the inner surface 15c is formed in an arc shape on the inner peripheral portion 15a side. The outer peripheral portion 15b side is formed flat.

The front shroud 16 has an inner peripheral portion 16a.
Is bent to have a substantially L-shaped cross section, and the outer peripheral portion 16b side is formed to be slightly inclined toward the rear shroud 15 along the outer edge direction. A fluid inlet 18 communicating with the cooling water supply passage is formed between the inner peripheral portion 16a of the front shroud 16 and the inner peripheral portion 15a of the rear shroud 15.

As shown in FIGS. 1 and 2, each of the vanes 17 has an outer peripheral portion 15b, 16 of each shroud 15, 16.
Radially formed on the b side, each is bent in a spiral shape opposite to the rotation direction, and each outer end edge 17b is extended to the outer end edges of both outer peripheral portions 15b and 16b. On the other hand, the inner edges 17a and 17c are formed so as to be adjacent to each other and alternately inclined in the opposite direction.

That is, as shown in FIG. 1, each of the adjacent vanes 17 has an inner edge 17a on one side which is formed to be inclined downward from the rear shroud 15 toward the center of the front shroud 16 and on the other side. Edge 17c is front shroud 16
To the inner peripheral portion 15a side of the rear shroud 15 in a downwardly sloping shape, and are formed in a cross shape with each other on the fluid inlet 18 side.

Therefore, according to this embodiment, the downwardly inclined vane 1 is provided on the inner peripheral portion 15a side of the rear shroud 15.
Since 7 are lined up at intervals, each inner edge 17 of each vane 17
The total area of the fluid inlet 18 near a and 17c increases. Therefore, even if the number of vanes 17 is increased, the area of the fluid inlet 18 near each vane 17 is prevented from being reduced.
Therefore, the decrease of the fluid pressure near the inner edges 17a and 17c is suppressed, and the occurrence of cavitation is prevented.

Moreover, the inner edge 1 of the one side vane 17 is
7a is formed so as to be inclined downward toward the center of the front shroud 16 and is inclined in the same direction as the flowing direction of the cooling water flowing into the fluid inlet 18, so that the collision of the cooling water with the inner edge 17a is reduced. To be done. As a result, in combination with the effect of preventing the area of the fluid inlet 18 from decreasing, the pump efficiency is prevented from decreasing.

The inner end edges 17a, 1 of each vane 17 are
The inclination angle of 7c is appropriately set appropriately according to the pump capacity, specifications, and the like.

[0020]

As is apparent from the above description, according to the closed type pump of the present invention, since the inclination directions of the inner edges of the adjacent vanes are opposite to each other, the fluid inlets near the respective inner edges are formed. The number of vanes can be increased without reducing the total area of the. As a result, the pump efficiency can be improved while preventing the occurrence of cavitation.

Moreover, since the inner end edges of the respective vanes are simply formed so that the inclination directions of the inner end edges are different from each other, the forming process is easy and the cost rise can be suppressed.

[Brief description of drawings]

FIG. 1 is a sectional view taken along the line X in FIG. 2 showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is a sectional view taken along line CC of FIG. 2;

FIG. 5 is a sectional view of a main part of a conventional closed type pump.

[Explanation of symbols]

 11 ... Pump casing 13 ... Drive shaft 14 ... Impeller 15 ... Rear shroud 16 ... Front shroud 17 ... Vane 17a, 17c ... Inner edge

Claims (1)

[Claims] 1. A plurality of vanes are provided between a front shroud and a rear shroud of an impeller rotatably driven by a drive shaft, and a vane is provided with a fluid inlet on an inner peripheral side of the front and rear shrouds as the impeller rotates. In a closed type pump that causes the inflowing fluid to flow out along the spiral inner surface of each vane, an inner edge of the adjacent one side vane on the fluid inlet side is directed from the rear shroud to a substantially central side of the front shroud. The closed type pump is characterized in that the inner end edge of the other side vane on the inlet side is formed in a downward slope from the front shroud toward the substantially center side of the rear shroud.